Magnetic input signals

Fig. 7.9.15 Magnetic sensor input signal modulated by the tone wheel rotation (blue line). Switching thresholds for defined switching to prevent unwanted switching (green line). Generated sensor output signal by the comparator circuit (red line)...

A sensor is typically a device that transforms signals from the mechanical, thermal, radiant, chemical, or magnetic domain to the electrical domain. A single sensor may be based on crosseffects between different signal domains to achieve the signal transformation to the electrical domain to be read by a human or an electronic instrument. These cross-effects are shown in Table 1, where the input signal domains are on the left-hand side, and the output signal domains are at the top (Meijer 2008). 

Components of a smart material (or system) include some type of sensor (which detects an input signal) and an actuator (which performs a responsive and adaptive function). Actuators may be called upon to change shape, position, natmal frequency, or mechanical characteristics in response to changes in temperatme, electric fields, and/or magnetic fields. 

The diagram below shows how the neutral position magnetic force on one side of the piston is checked by a force proportional to the reduced pressure Pa. The result is a direct and constant match between the input signal and the reduced pressure. 

A directly applied controlled magnetic force F is brought into exact counterbalance with a proportional hydraulic force. The appropriate output pressure in relation to the input signal i is controlled by Xp and X.,. Conversionis effected with a loss of < = 0.1%. 

With gate valves a controlled magnetic force F is brought into counterbalance with an elastic force, i.e., a dependent force. The input signal is allocated the appropriate cross-section for the valve with Xp and X.,. The decisive feature is hysteresis-free control in the area around the dydraulic middle position. Symmetrical or asymmetrical controlled cross-sections A can be controlled directly up to 700 mm. The Turcon CTo version with protection against over-speed rpm is available as a specially adapted gate valve. 

In order for electronic transmission systems to be less susceptible to interference from magnetic fields, current is used for the transmission signal instead of voltage. The signal range is 4 to 20 miUiamps. In each circuit or current loop, there can be only one transmitter. There can be more than one receiver, but not an unlimited number. For each receiver, a 250 ohm range resistor is inserted into the current loop, which provides a 1- to 5-volt input to the receiving device. The number of receivers is hmited by the power available from the transmitter. 

Table 4.1 Four-digit numerical values for all the input spectral parameters the real Re(v/,) and imaginary lm(v/<) parts of the complex frequencies Vk, and the absolute values dk of the complex amplitudes dk of 25 damped complex exponentials from the synthesized time signal Eq. (42) similar to a short echo time ( 20 ms) encoded FID via MRS at the magnetic field strength 80 = 1.5T from a healthy human brain [71]. Every phase 4>k of the amplitudes is set to zero (0.000), for example, each dk is chosen as purely real, dk= dk exp (Uj>k) = dk. The letter M denotes the feth metabolite...

In most systems the interface contains a switching device to multiplex other signals from the MS such as the total ionization and magnetic field sensing voltages used in certain aspects of data processing. Directed by an operator from an input terminal, the data are processed in the CPU under the control of programmes stored in a peripheral device. 

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